Time-to-digital converters (TDCs) are employed in digital phase-locked loops (DPLLs) to quantify the relative phase between the local oscillator (LO) output (usually a high frequency signal) and a reference clock (usually a low frequency signal). The quantization is obtained in the TDC by measuring the relative time between a signifying event in the LO output signal and a signifying event in the reference clock signal, such as selected rising/falling edges of the signals.